cos (π/12) × cos(5×π/12)的值
化简cos(π/12)*cos(5π/12)
若cos(5π12
已知cos(5π12
计算cos(a+5π/12)cos(a+π/6)+cos(π/12-a)cos(π/3-a)
已知cos(α+β)=12/13,cos(2α+β)=3/5,若β∈(0,π/2),求cosα的值.
cos方5π/12+cos方π/12+cosπ/12*cos5π/12 最后等于5/4的过程.
cos方5π/12+cos方π/12+cosπ/12*cos5π/12 最后等于4/5的过程.
求下列各式的值:(1)cos(-165°) (2)cos(7π/12) (3)cos(-61π/12) 求详解
cosπ/12+(根号3)×sinπ/12的值
跪求 计算cos(-25π/12)的值,谢谢
若cos(α-3π/2)=1/5,求-cosα的值.
化简cos(π/12-α)-根号3cos(5π/12+α)